The present invention relates to an air bag system for expanding an air bag for protecting a passenger of a vehicle when a collision of the vehicle is detected and, more particularly, to a vehicular air bag activation control system for activating an air bag in the position which is determined on the basis of a collisional direction.
The air bag system of this kind detects a collision on the basis of the ON action of a switch accompanying either an acceleration (including a deceleration as in the following) or a crush of the vehicular body, and ignites an inflator in response to the detection signal to produce gases so that the air bag may be expanded with the gases between the passenger and the inner wall of the vehicular body. In the prior art, an ordinary vehicle is frequently equipped with the air bag system for protecting the driver. In recent years, however, there has been developed the technology of mounting the air bag system additionally in front of the passenger's seat or in the side door.
On the other hand, the collisional accident of a vehicle has various modes, in which the collision will not always be limited to accurately longitudinal or lateral directions, for example, but may be directed obliquely or followed by a turn of the vehicular body. Moreover, the load or acceleration to be exerted by the collision may be so diversified as to act in the opposite direction to the collisional direction due to a vibratory return after the collision.
Therefore, in the vehicle equipped either with the air bag systems for front and lateral collisions or with air bags for lateral collisions at righthand and lefthand doors, as described above, the active air bag system, i.e., the air bag system to be activated has to be determined in accordance with the collision mode so as to protect the passenger properly from a secondary collision resulting from the primary collision. In the prior art, however, no system has been known for activating a plurality of air bag systems selectively in accordance with the mode of a collision, although there have been developed either the sensor having a high sensitivity, the system for detecting a collision reliably or the system for preventing any malfunction.